com.wxpn.tutorial是什么？

"com.wxpn.tutorial.db.ConnectionPool" is called fully qualified class name of class "ConnectionPool", or its full name.

"com.wxpn.tutorial.db" is its package name.

you "import" the fully qualified class name into your class, so that you can use the short name "ConnectionPool" within you class.

you import other classes so that you don't need to write them again.

这是java的类路径。com.wxpn.tutorial.servlet具体讲就是一个servlet